Manufacture of alloys



May 8, 928. 1,668,642

w. M. GROSVENOR ET A1..

MANUFACTURE oF ALLoYs" Filed Feb. 5. 3.92.5

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INVENTORS ATTQRNEYS Patented May 8, 1928.

UNITED STATES PATENT OFFICE.r

WILLIAM I. GROSVEN'OB AND VICTOR P. GEBSHON, 0F NEW YORK, N.

'Y,; SAD) GERSHON ASSIGNOR-TO SAID GROSVENOR.

IANUFACTURE F ALLOYS.

Application led. February 3, 1925. Serial No. 6539.

Our invention relates to improvements in the manufacture of alloys andmore particularly to base alloys adapted for the manufacture of whitegold and method of making white gold therewith. As is known in the art,white gold is an alloy of gold, nickel and zinc, sometimes containingalso one or more other metals such as copper or palladium. White goldwas formerly made by melting for example parts gold and adding to themolten gold and melting therein 4 parts of' nickel and 1 part of zinc by-weight, the Wholebeing covered with a suitable flux. The maindiiliculty with this method was that, in spite of the flux, more or lesszinc is volatilized and lost so that the resulting alloy is variable andsuch variations, particularly in respect of the quantity of zinc, resultin an inferior if not useless gold alloy, and only in the hands ofskilled manufacturers of alloys is it possible to obtain commercialresults, and even then such alloys often contain oxides produced vby theoxygen from the air of hydrogen compounds caused by the action ofhydrogen from the moisture ofthe air, which render the alloy excessivelybrittle. Therefore, the process is not well adapted for the averagejeweller to carry out. .Most jewellers, furthermore, prefer to make uptheir own gold, because the gold they require varies as to number ofkarats and by making up their own white gold from line gold and basemetal they can get any karat gold they desire and do not have to carryin stock substantial quantities of made up gold of different karatsinvolving relatively large carrying charges. To meet this demand of thejewellers attempts have been made to supply the jewellers with basemetals or alloys which the jewellers might readilyF alloy with fine goldin any desired proportion. The desideratum has been a base alloycontaining nickel and zinc in proportions to make white gold. In thelirst mentioned method of making white gold by adding the unalloyednickel and zinc to the molten gold, it is known that the zinc should beabout one fifth of the base metal, e. g. if nickel and zinc alone areused to form the base metal to be alloyed with the fine gold, 4 parts ofnickel to 1 part by weight of zinc would be used, and if for example itwere desired to produce an 18 karat white gold, 4 parts nickel and 1part zinc and 15 parts of line gold would be used. A base alloy of about80% nickel and 20% zinc suitable to be thus alloyed `with gold, has not,so far as we are produced. It is well known/that zinc boils andvaporizes at a temperature well below the melting point of nickel and ifnickel be added to molten zinc it is found that only a relatively smallpercentage of the nickel will be taken up, while if zinc be added tomolten nickel or the two heated together to a temperature sullicient tomelt them, a large part of the zinc volatilizes making it impossible toobtain a resulting nickel-zinc alloy .of predetermined composition ofanything like thek 80-20 proportion, which must be quite closely adheredto in so far as the proportion of zinc is concerned if a satisfactorywhite gold is to be obtained.

To obtain an alloy which jewellers might melt up with gold to make suchwhite gold, it has been suggested that an alloy containing the zinc andabout equal parts of copper and nickel be used. This base alloycontained over 40% copper. By using this copper it was found that over15% of zinc and about 40% of nickel could be gotten in the resultingbase alloy of nickel, copper and zinc. When, however, this base alloywas melted with fine gold to make 18 karat or other usual karat whitegold, it was found that the resulting gold was tinged with yellow or redand oil' color and did not have that desirable whiteness substantiallylike that of platinum.

To avoid this and reduce the amount of -copper in the resulting gold ithas been suggested that two metals be furnished the jewellers, one beingmerely nickel and the other an alloy of copper and zinc with or withouta small amount of nickel and/or palladium. In this way the amount ofcopper introduced into vthe final gold has been reduced to about 10% 4ofthe base metal,

whereby the resulting goldis of much better color. This method has thedisadvantage however, that two base metals must be carefully weighed outas well as the gold and a mistake in weighing out either of the two basemetals is likely to result in a subst-antial change in the proportion ofzinc in the resulting alloy which in turn will result in an inferiorwhite gold if not a useless alloy. Likewise mistakes are frequentlyaware, been heretofore made by interchanging one base metal or alloy foranother. Also there is danger of loss of zinc by volatilization. Themethod is therefore not only inconvenient but quite dificult ofmanipulation, uncertain in result, and a single base alloy suitable formelting with fine old in proportions to make 18 or other usua karat goldhas been long sought.

To accomplish this result we have produced a new base metal comprising asubstantially uniform and homogeneous alloy containing nickel and zinc,or a material containing nickel and zinc alloyed together, the zincbeing about 20% of the alloy or material and the nickel about 80% (or ifsome other metal or metals are incorporated, the nickelbeing about 70%or over, the alloy or material having the characteristic that whenmelted and allo ed for example with 3 times its weight of ne gold, theresultant gold alloy not only exhibits a whiteness substantially likethat of platinum but it also is capable of being cast and rolled formaking jewelry. We have further' discovered that such a base alloycontaining about 20% zinc can be produced by melting the zinc and nickel(with or without a small amount of other metal or metals) under pressurewhereby the volatilization of the -zinc is prevented so that alloys ofnickel and zinc and containing a substantially accurate predeterminedpercentage of zinc can be satisfactorily obtained.

For this purpose we prefer touse an apparatus like that shown in theaccompanying drawings in which Fig. 1 is a vertical section of theapparatus. Fig. 2 is a horizontal section taken on the line 2-2 of Fig.1, and

Fig. 3 is a vertical section of the lower part of the apparatus taken onthe line 3--3 of Fig, 1.

hel apparatus shown comprises a cast iron dish-like container 4 providedwith flanges 5 to which a cover member 6 may be tightly secured by bolts7, the cover acting to seal the container air-tight. The container islined with a thick layer 8 of heat insulating material ysuch as asbestosorisilocell. Fitting snugly within this heat insulating material is atrough or vessel 9 of carbor'undum, within which are located a pluralityof dishes 10, 11 and 12, made of suitable refractory material, a layerof carbon resistor grains 13 extendin around the bottom, sides and endsof the dis es 10, 11 and 12 between them and the inside walls ofcarborundum vessel 9.

Screwed into the ends of the container 4 are cast iron pipes 14 and 15provided on their outer ends with flanges 16 and 17 respectively. Carbonor graphite electrodes -18 and 19 extend through this pipe respectivelyand through the end walls of the vessel 9 into the carbon resistorgrains 13 in order to make electrical connections therewith. Theelectrodes 18 and 19 are held messes .their outer endsfrom which leadflexible electrical conductor strips 22 to the heavy electricalconductors 23 and 24 respectively. The conductors 23 and 24are held inbakelite bushings 25 and 26 respectively secured into plates 30 and 3l,vwhich plates are secured to fianges 16 andi17 wherebythe bushings aresecured with respect to and close the outer ends of the pi es 14 and 15respectively. When in use t e dishes 10, 11 and 12 are preferablycovered on top with a clay plate 27. The cover 6 has an' iron pipe 28screwed into an opening therethrough'. The pipe 28 is flanged at itsouter end and -to this iiange is secured an apertured disc 32. Abakelite bushing is screwed into the aperture of the disc 32 and throughthis bushing extend electrical connections to a thermocouple 33 formeasuring the temperature'in one of the dishes. The cover 27 is suitablyapertured to permit the insertion of thermocouples therethrough into theother respective dishes.

The apparatus described provides a suitable electric furnace withinwhich the new alloy may be made. By applying a suitable potential to theelectrodes 18 and 19, current will pass through the body of carbonresistor grains 13 causing the production of an intensive heat thereinto heat the material placed within the dishes 10, 11 and 12. The cover 6is provided with a pressure gage 34 for measuring the pressure withinthe furnace and also with a pipe connection 35 through which gas underpressure may be introduced into the furnace.

In operation we place the nickel' and zinc in the proper proportions andin the form of shot or line pieces, in the dishes 10, 11

`and l2, and cover the metals'with a suitable quantity to heat themetals in the vesselsy to alloying temperature. Or, instead of beingevacuated, the air may be removed from the apparatus by displacementwith nitrogen gas. Also the atmosphere should be preferably free ofhydrogen which may be generated by the action of CO or C on the moisturein the air. When making an alloy of 20% zinc and 80% nickel it isordinarily suilicient to maintain the pressure in the apparatus at from10 to 15 atmospheres. However, other metals includi'n copper may besubstituted rfor part vof t e nickel but for reasons above given, weprefer to keep the percentage of copper to about 10% or less and thepercentage of nickel to about or over. The alloy has a melting pointWell above the boiling point of zinc at atmospheric pressure, but bymelting and alloying under pressure, any substantial amount of zinc isprevented from boiling oii or being lost to the alloy by volatilization.The properties of the alloy seem to be seriously affected by smallamount of various impurities and by alloying in an atmosphere ofan inertgas such as nitrogen, the likelihood of such impurities .becomingincorporated in the base alloy as well as loss by oxidation of metal ismaterially reduced.

The resulting base alloy may be readily alloyed with 3 times its weightof ine gold to make 18 karat gold or any usual proportion and this iseasily done by the various jewellers Vin a manner with which they areaccustomed. vThe vresultant gold alloy not only exhibits a whitenesssubstantially like that of platinum but it is also capable of beingreadily cast and rolled for making many kinds of jewelry. It will beunderstood that any other suitable type of furnace may be used insteadof that described.

While we have described our improvements in great detail and inconnection with a preferred embodiment thereof, we do not desire to belimited to such details or embodiment since many changes andmodifications may be made and the invention embodied in Widely dierentforms without departing from the spirit and scope of the improvements intheir broader aspects. Hence we desire to cover all modifications andforms coming within the language or scope of any one or more of theappended claims. A

What we claim as new and desire to secure by Letters Patent is:

1. A substantially uniform and homogeneous alloy containing about 80% ofnickel and about 20% of zinc, having a melting point above the boilingpoint of zinc and having the characteristic that when alloyed with 3times its weight of tine gold the resultant gold alloy not only exhibitsa whiteness substantially like that of platinum but it also is capableof being cast or rolled for making jewelry.

2. A substantially uniform and homogeneous alloy containing nickel andzinc, the zinc being about 20% of the alloy and the nickel about 70% orover, the alloy having a melting point above the boiling point of zinc,and having the characteristic that when alloyed with 3 times its weightot' tine gold the resultant gold alloy not only exhibits a whitenesssubstantially like that of platinum but it also is capable of being castor rolled for making jewelry.

3. A substantially uniform and homogeneous alloy containing nickel andzinc, the zinc being about 20% of thealloy and the nickel about 70% ormore, and having the characteristic that it is capable ot being alloyedwith 3 times its weight of line gold producing a resultant gold alloywhich not only exhibits a whiteness substantially like that of platinumbut which also is capable of being cast or rolled for jewelry.

4. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture of about 20%zinc and about 807;) nickel to alloying temperature in an inertatmosphere and under pressure suiiicient to prevent any substantialvolatilization of the zinc.

5. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture containing zincin the proportion ol about 20% and nickel in the proportion of about 70% or over, to alloying temperature and under pressure sufiicient toprevent any substantial volatilization of the zinc from the mass.

6. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture containing zincin the proportion ot' about 20% and nickel in the proportion of about70% or over, to alloying temperature in an inert atmospheresubstantially free of hydrogen and oxygen and under sufficient pressureto prevent any substantial volatilization of the Zinc from the mass.

7. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture containing zincin the proportion of about 20% and nickel in the proportion of about 70%or over, to alloying temperature in an atmosphere of nitrogen and undervsutlicient pressure to prevent any substantial volatilization of thezinc from the mass.

8. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture of about 20%zinc and about 80% nickel to alloying temperature and under pressuresuicient to revent any substantial volatilization of tiie zinc.

9. The method of making a base alloy capable of being alloyed with goldto make white gold, which consists in heating a mixture containing zincin the proportion of about 20% and nickel in the proportion ol about 70%or over, to alloying tempetrature and under pressure sufiicient toprevent any substantial volatilization of the zinc from the mass, andwith a flux covering the upper surface of the batch.

10. A single substantially uniform and' of about four parts to one partrespectively, having a complete melting point above the normal boilingpoint of the zinc therein and producing when alloyed with fine gold inproportions to make 18 karat gold a gold alloy exhibiting substantiallythe whiteness of platinum and adapted for casting or Jthe characteristicthat when alloyed with rolling.

11. The method of making a base capable of being alloyed-With gold tomake white gold which consists in heating a mixture consisting mainly ofnickel and containing about 20% Zinc, to alloying temperature underpressure suicient .to prevent any substantial volatilization of thezinc.

12.'The method of making a base capable of bein alloyed with gold tomake white gold Wi consisting mainly of nickel and containing` about 20%zinc, to alloying temperature in an atmosphere of nitrogen and underpressure suicient to prevent any substantial volatilization ofthe zinc.

13. An alloy material containing zinc and nickel alloyed together, thematerial containing about 20% zinc 'and about 70% or over of nickel andhaving the characteristic that when alloyed with 3 times its weight ofline gold, the resultant gold alloyfnot only exhibits a whitenesssubstantially like that of platinum but it 'also is capable of beingcast or rolled for jewelry.

14. An alloy material containing zinc and nickel alloyed together, thematerial containing about 70%. or over of nickel and having thecharacteristic that when alloyed with 3 times its Weight of fine gold,the resultant gold alloy will no t only exhibit a whitenesssubstantially like that of platich consists'in heating a mixture.

num but it also is capable of being cast or rolled for jewelry.

15. 'Ihe method of making white gold which consists in first making abase alloy material of zinc and nickel alloyed together, the materialcontaining about 20% of zinc and about 70% or over of nickel and having3 times itsweight of fine gold, the resultant gold alloy will not onlyexhibit a whiteness substantially like that of platinum but it also iscapable of being cast or rolled for jewelry and then alloying this basealloy with gold in proportions to make white gold.

16. The method of making white gold which consists in first forming abase alloy material containing zinc and nickel alloyed together, thematerial containing about 70% or over of nickel and then alloying thisbase alloy material with gold to produce white gold.

17. The method of making white gold which consists in lirst forming` abase alloy material containing zinc and nickel alloyed together, thematerial containing about 70% oiwer of nickel and having thecharacteri'stic that when alloyed with 3 times its weight of finegoldthe resultant gold alloy not only exhibits a whiteness substantiallylike that of platinum but also is capable of being cast or rolled tomake jewelry, and then alloying said base metal with gold in proportionsto produce white gold.

In testimony whereof we have signed our names to this specification.

WILLIAM M. GROSVENOR. VICTOR P. GERSHON.

